Main menu

Post navigation

5) Further testing indicated a significant difference in the ang

5). Further testing indicated a significant difference in the angular standard deviation of the Δheading data, with the SD of the Δheading distribution after the playback significantly lower than would be predicted from rotated data (Fig. 6). This indicates that the whale maintained a more directed course after the cessation of the killer whale playback (Fig. 2, 3). The whale’s course heading was centered on a northerly direction (Fig. 7), which took it directly away from the source of the playback, and towards the only deep-water exit of the TOTO canyon. It should be noted that, while the experiment was designed to test for a change this website in movement patterns, as measured by heading, the angular standard deviation

test was developed post hoc. The NLR tests for any change in the Selleck EPZ6438 distribution of the Δheading data. Once it was determined that there was a significant difference between the distribution of the whale’s heading before and after the killer whale playback, we then chose to focus on the variation in heading, as measured by the angular standard deviation. This decision was influenced by the observed results, and ideally, the test developed after this examination of the data would be utilized to confirm these findings

in future playback experiments. However, the difficulty involved in finding and tagging beaked whales made this unfeasible in this case. One goal for this paper is to encourage similar future playback experiments to use this method to test for similar responses. This prolonged, directed avoidance in reaction to the killer whale playback put increasing distance between

the whale and the location of the playback, similar to that seen in predation avoidance by other species. Minke and sei whales, which employ this flight strategy, have been observed to beach themselves while being chased by killer whales (Ford et al. 2005, Ford and Reeves 2008). The reaction observed here may be an antipredator response similar to the flight reaction of baleen whales to killer whale predators (Ford et al. 2005, Ford and Reeves 2008) and it is possible that this sustained directed flight puts beaked whales at risk for stranding as well. It is not apparent whether the strandings of baleen whales were the result of an intentional avoidance MCE公司 strategy, or if the whales inadvertently ran into the shallows due to their fixed course, or were perhaps driven ashore by the pursuing whales (Ford et al. 2005, Ford and Reeves 2008). Regardless of the reason for stranding, in only one observed case was a minke whale able to work its way off the beach after the killer whales departed. Therefore, if it is an intentional strategy, it must be a last ditch very high risk effort, motivated by extreme predation pressure. If Blainville’s beaked whales utilize a similar strategy, then in extreme cases this may put them at risk for stranding.